Safety carriage for crane booms



E. T. FOSTER SAFETY CARRIAGE FOR CRANE BOOMS Aug. 2, 196e 4 Sheets-SheetI 1 `Filed July 16, 1962 om @i INVENTOR.

EDWARD T FOST ER 13%/ Aug 2, 1966 E. T. FOSTER 3,263,383

SAFETY CARRIAGE FOR CRANE BOOMS Filed July 16, 1962 4 Sheets-Sheet 2 F 4 INVENTOR EDWARD FOSTER Aug' 2, 1966 E, T. FOSTER SAFETY CARRIAGE FOR CRANE BOOMS 4 Sheets-Sheet 3 Filed July 16, 1962 INVENTOR. EDWARD T FOSTER Aug- 2, 1956 E. T. FosTER SAFETY CARRIAGE FOR CRANE BOOMS 4 Sheets-Shree?l 4.

Filed July 16, 1962 0mm www o INVENTOR. EDWARD T FOSTER United States Patent O 3,263,383 SAFETY CARRIAGE FOR CRANE ROOMS Edward T. Foster, 4360 Nicholas, Omaha, Nebr. Filed July 16, 1962, Ser. No. 299,963 1 Claim. (Ci. 52-143) This invention relates to motor cranes having booms some of which are one hundred feet long or more.

More particularly it is an object to provide means for achieving safety while the crane is being moved from one location to another.

Modern practice frequently requires that such cranes move often and to make as .many as 4 or 5 work stops in one day. Two operators are used, one at the front to drive the mobil-crane, one at the rear to rotate the boom supporting turntable to swing the boom with respect to the carrying truck or tractor. The present method -of moving is an expedient that is fraught with potential hazard to both life and property.

Yet booms must 'oe allowed to be swung by the second operator at the rear of the rig for otherwise such rigs are so long that the turning area needed at a corner would at times consume more than an entire road intersection. Or turning around a curve would cause the boom to project dangerously into the other highway lane.

The present prior art method involves the swinging of the giant booms at a low level by the rear operator while the vehicle is being driven through the streets by the forward operator or driver of the rig.

The specific hazards and unsafe practices are:

(a) The boom is at a low level where greatest difficulty and most power is needed to control swing.

(b) The momentum of a heavy G-foot boom when swinging is very great. The wide and rapid swings required to maneuver the heavy crane booms around corners and curves along a route of travel tax the capacity of the machine and the skill of the operator.

(c) There is a strong possibility of striking pedestrians, vehicles, and buildings during such movements.

(d) I have seen motorists and pedestrians pass under such booms while they are in this least stable and highly stressed condition.

(e) Even while machine is stationary and not traveling over bumpy roads and the boom is carrying no load in the near horizontal position required for traveling, all elements of the crane boom, boom line rigging and chassis are under inordinately heavy stress. An upright boom in contrast is stressed mostly longitudinally, in the direction of greatest boom strength.

(f) As the crane moves over uneven streets, railroad tracks, intersection dips, etc., this high stress is accentuated by the whipping action of the long extended heavy boom. This recurring heavy loading due to impact gradually leads toward meal Ifatigue and failure in any one of many parts of the crane.

It is, therefore, an object of this invention to provide a solution to the problem which achieves the following objectives:

(a) Eliminates most of the potential of striking pedestrians, veh-icles, and property.

(b) Eliminates conditions that cause recurring high stress loading.

(c) Preserves maneuverability now accomplished by horizontal boom swinging by the rear operator during travel.

(d) Is light, simple and easily changed from work to travel position and vice-Versa.

(e) Is readily adaptable to cranes of various sizes and manufacture.

(f) Is capable of economical production and distribution.

Patented August 2, i963 A main object of this invention is, therefore, to provide the concept of a safety carriage for supporting the giant crane boom while the crane is being moved.

A further object is to provide a boom safety carriage which can quickly be attached' for travel and detached for work by the regular two-man crane crew working alone.

Yet another objective is to provide a supporting carriage near the rearmost end of the crane to give it the appearance of continuity which will prevent pedestrians and motorists from getting into the very dangerous position under the boom.

Another object is to provide a device which will greatly reduce rear axle and wheel loading to within the legal limits which are today greatly exceeded.

A further object is to provide a carriage which can be used to carry a boom with attached jib section by shortening the jib tie-back cables.

A particular object is to provide a device which greatly enhances the steerability of the crane carrier by eliminating the tendency of its front steering wheels to lift off the ground, and also to preserve the traction at the front wheels which is otherwise at times lost by the weight of the extended boom, especially when the crane hits a dip in the road.

Other objects are to provide a device which will legalize over-the-road rear axle loads in many states without boom removal and will require only overlength-not overweight and overlength permits, and which will permit the crane gantry to be retracted permitting least vertical height for clearance of wires and overhead structures.

A very important objective is to eliminate the worst part of the bouncing or whiplash effect at the rearward ends of the booms which are, at present, only cable-supported in travel. At present, the resiliency of cables permits a boom to whiplash up and down quite heavily.

Yet a further object is to provide relief for the center pin of the crane which is under particular stress, along with other parts, from the whipping up and down of the boom when in the horizontal position of maximum lateral extension.

A particular object is to relieve the strain on the rear operator who has formerly had to keep his eyes fixed on the boom ready for instant action and swing it in such ways that its rearward end, sometimes feet away, does not swing a few degrees too far as would place it in the path of traffic in another lane and whereby the rear operator can be relatively relaxed since the boom will trail in its own lane of the highway not nearly so affected by turning movements of the crane truck because it is pivoted, as is a trailer at its hitch, instead `of being relatively rigidly supported to the vehicle by cables only.

Other and further objects and advantages of the present invention will be apparent from the following detailed description, drawings and claims, the scope of the invention not being limited to the drawings `themselves as the drawings are only for the purpose of illustrating a way in which the principles of this invention can be applied.

Other embodiments of the invention utilizing the samei or equivalent principles may be used and structural changes may be made as 4desired by those skilled in thc art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIGURE 1 is `a diagrammatic side elevation of a mobilcrane shown traveling across a roadway surface with the safety carriage of this invention attached to its boom.

FIGURE 2 is `a side elevation of a tower-type mobilcrane shown on a roadway with its jib portion folded under its inner boom portion and with a safety carriage FIGURE 5 is a detail of a portion of a crane boom shown with a safety carriage attached thereto.

FIGURE 6 is a sectional view taken along the line 6-6 of FIGURE 5.

FIGURE 7 is a top plan view of the parts shown in FIGURE 5, but with broken away sections of boom supports visible.

FIGURE 8 is a side elevation similar to FIGURE 5, but showing boom supports in position for supporting a boom and showing the lower portion of the caster wheel assembly as absent, having been removed from the upper portion of the caster wheel assembly.

Referring to FIGURE 1, a mobil-crane is there generally indicated at 10 having a truck portion 12 carrying a crane having a control housing 20 mounted to pivot on a mounting 30 about a vertical axis.

The housing 20 has a counter-weight 40 on its rearward side for counterbalancing the great weight of the boom 50 of the crane, which latter in FIGURE 1 is shown extending substantially horizontally rearward from the truck 10.

The boom 50 is pivotally attached as shown at 52 to the frame 54 supporting the control housing 20.

It will be understood that the boom 50 can be in a multiple of sections as is conventional.

A safety carriage generally indicated at 60 is provided by this invention for attachment under the boom S0 and to support the great weight thereof.

The safety carriage 60 is preferably attached to the rearwardmost section 62 of the boom 50, as best seen in FIGURE 5. The sectional nature of the boom is shown only in FIGURE 5, as it is not a part of this invention. The reason that the safety carriage 60 is attached to the `rearwardmost section of the boom is because when it is designed to t this section, it will thereby fit all booms of conventional construction and extra sections of a boom can be added to its center without affecting the use of the safety carriage 60.

A second reason for placing the safety carriage 60 on the outermost rearward section of the boom, and particularly at the inner end of the outermost section, is because this is a very effective position, in many cases being approximately in the center of the rearward half of the boom.

In FIGURE 5, the caster wheel assembly has an upper mounting portion 64 and a lower portion 66, which latter has a wheel 68 for engagement with the roadway 70.

The caster wheel 63 is mounted upon an axle 70 and a bearing plate 74 having a substantially or at least approximately upper horizontal surface 84. A pair of spaced arms 88 extend downwardly from the plate 74 and are connected to the axle 70'. The arms 8S extend upwardly from the axle 76' at an inclination to the vertical and connect to the plate 74 which can also be called a lower bearing means 74 which has as its main purpose providing the substantially horizontal bearing surface S4.

A pivot shaft 100 is attached to the lower bearing member or plate 74 in the sense that the shaft 100 extends through a suitable vertical opening 120 in the lower bearing member 74, the shaft 120 having a head 124 on its lower end and a removable nut 130 on its upper end. The head 124 has a washer 130' above it which latter bears against a horizontal bar 138 which extends across the underside of two vertical bars 140 disposed one on each side of the axle 100, the vertical bars having their upper ends disposed against the bottom side of the bearing member 74, and preferably connected thereto.

The horizontal bar 138 is preferably connected to the vertical bars 140.

An upper bearing member or upper plate is disposed above the lower bearing member or plate 74, the upper bearing member 170 having a lower surface 172 which is substantially horizontal and which is disposed against the upper bearing surface 84 of the lower bearing plate 74.

The upper mounting por-tion 64 of the caster wheel assembly 60 comprises a mounting tube 180 which receives the pivot shaft 100. The lower end of the mounting tube is disposed against and connected to the upper bearing member 170 and is adapted to receive the upward thrust of the upper bearing member or plate 170 1n use.

Above the mounting tube 180 and attached thereto is a boom engagement plate 210, best seen in FIGURE 6, which latter is adapted to engage the undesurfaces of longitudinal members 220 of the boom rear section 62.

The shaft 100 extends through an opening 230 through the boom engagement plate 210 and the nut 130 `retains the shaft 100 in place.

In accordance with this invention, a standard boom section 62 is modified by attaching ears 270 to its lower longitudinal members 220 which are disposed on the underside during road travel. The ears 270 extend vertically upward and have openings therein along the line extending transversely of the boom and preferably at a right angle with respect to the boom. The ears 270 can be called attachment ears 270 and there are preferably an inner pair of ears 270 and an outer pair of ears 270, each pair having two ears 270 in number and each pair of ears 270 being spaced apart longitudinally of the boom and receiving therethrough an attachment pin 300. There are two attachment pins 300, one extending through the inner ears 270 and one extending through the outer ears 270.

Anchor plates G40 are attached at their lower ends to the boom engagement plate 210 and extend upwardly, each attachment plate 340 having an aperture therethrough extending transversely of the boom 62 and each receiving a respective end of a removable attachment bolt 300, having a head 350 and a nut 354 at its ends. Four gussets 360 are attached to the bottom of the boom engagement plate 210 and extend -down to and are se- -cured to the top of the upper bearing Imem-ber 170. An inner side of each gusset 360 is attached to the mounting tube 180.

The gussets 360 each extend at 90 degrees with respect to the longitudinal `centerline of the boom and each gusset G60 extends at 90 degrees with respect to each adjacent gusset.

A pair of boom support .socket tubes 390 are mounted one on the forward side of each of the forward ones of the four :gussets 360. Each boom support socket tube 3S() is ydisposed at an inclination of approximately 30 degrees with respect to the vertical, each being inclined forwardly at its lower end and having its upper rearward end irmly secured t-o the respective gusset plate i360 and to the boom engagement plate 210.

The projecting lower end of each lboom support socket tube 390 is provided with apertures 394, which as best seen in FIGURE 8, are spaced apart vertically `and are for the purpose of receiving a pin 398 'which is adapted to extend through the boom support socket tube 390 and also through an opening not shown in a boom support or boom leg 400. Each boom leg 400 is elongated sufticiently that when it is txed in -its respective boom support socket tube 390, its lower end will extend downwardly suiciently to hold the caster wheel assembly upright to facilitate its installation or removal by removing the two attachment bolts 300.

At times when the 'boom support or boom legs 400 are not needed, they are easily removed.

Operation As best seen in FIGURE 1, it will be seen that in operation, the safety carriage adequately supports the great weight of the long boom relieving the stress that was entirely formerly carried by a cable 1500 extending from the outer end of the boom over a pulley 506 and thence to a winch not shown in the control housing 20.

It is the cable 500, which when used to support the boom in the horizontal position, stretches and gives rise to the whiplash effect of the outer end of the otherwise unsupported boom.

Because the boom 50 is pivoted at 52, the boom `50 and its support carriage 60 form a trailer to the end that the boom 50 -follows the truck portion 12 of the crane as the truck turns corners.

For this reason, an operator at the rear end of the rig and controlling the 'boom 150 with visibility through a window 5-12, seen in FIGURE l, now can be relieved of the strain he has formerly been under because the rearward end of the boom `will simply trail and will not need to be swung from side to side nearly so often.

As best seen in FIGURE 3, when the crane is in operation, the safety carriage 60 can be left on the boom, if desired, although it can also be removed entirely, or its lower portion 466 can be removed to give further clearance.

Referring to FIGURE `4, a tower crane is there shown and all elements of it are given the same numbers as regards the crane of FIGURE 3 with the exception of the boom of the toiwer crane which is .seen at `600 and which has two sections, an inner section 610 and an outer section 512, the latter `being pivoted to the inner section 610 at a pivot 620.

As best seen in FIGURE 2, the outer boom section or jib 612 of the tower crane of FIGURE 4 can be folded iback under the inner boom sections 6'10 with the outer end of the jib 612 held up Iby a special cable `6130 connected suitably to the inner boom section '610.

When the jib 612 is in this position, a wheel carriage generally indicated at 60 in FIGURE 2 can be connected to the underside of the jib 612 at a point approximately three-fourths of the distance rearwardly from the forward end of the inne-r boom section 610.

-It is common for a jib 612 to have a greater inclination to ,its undersurfaces when they are in the position shown in FIGURE 2, and for this reason, suitable means 640 can be used to space the boom engagement plate 210 away from the jib 612.

Referring to FIGURE 4, the operation of the entire tower crane is entirely possible with wheel carriage 60 of this invention attached to it, in which the wheel carriage 60 is on the upper side of the jib 612 lwhen the latter is in operating position.

As thus described, it is believed that this invention has fulfilled the objects above set forth.

From the foregoing description, it is thought to be obvious that a safety carriage :for crane booms constructed in accordance with my invention is particularly well adapted for use, by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my invention can be changed and modided without departing lfrom the principles and spirit thereof, and for this reason, I do not wish to be understood as limiting myself Kto the precise arrangement and Iformation of the several parts herein shown in carrying out my invention in practice, except as claimed.

I claim:

For supporting a mobile crane having a long and heavy boom projecting substantially horizontally rearwardly during road travel, a caster wheel assembly disposable generally beneath said boom for supporting at least a substantial portion of the weight of the boom, and removable means for attaching said caster wheel assembly to said boom, said caster nvheel assembly having an upper mounting porti-on and a lower portion comprising a wheel, means for attaching said upper mounting portion to said boom, means fixed to said upper mounting portion and providing elongated sockets disposed approximately upright, elongated temporary boom supports removably ldisposable in said sockets and of a length suftlicient to hold said caster wheel assembly upright to facilitate its installation or removal, said. 'boom supports being at least two in number and having lower groundengaging ends disposed in use for engaging the ground at two points spaced apart with respect to the point at :which said caster wheel engages the ground whereby the two ground-engaging points of said boo-m supports and the ground-engaging point of said caster wheel are all sufficiently spaced for supporting said caster Wheel assembly uprig-ht when it ,is detached from said boom.

References Cited by the Examiner UNITED STATES PATENTS 1,171,569 2/1916 Wanda 16-30 1,739,716 12/'1'929 Fisher 2SC-78 2,094,050 `9/1937 Wachter 280-78 2,564,996 `8/1951 Rasbach 280--78 3,020,063 2/-1962 Warren 280-l50.5

FOREIGN PATENTS 1,171,164 1/-1959 France.

FRANK L. ABBOTT, Primary Examiner.

RICHARD W. COOKE, JR., Examiner.

L. R. RADANOVIC, Assistant Examiner. 

